APPLIED CATALYSIS B-ENVIRONMENTAL
·
2025
·
IF 21.1
Bei Jiang,Mengya Xu,Ling Zhang,Wenjing Wang,Xin Qin,Shenyan Xu,Chunyu Che,Chuanqi Zhang,Wenzhong Wang
Open-shell organic radicals, characterized by their unique spin states, typically exhibit exceptional photothermal conversion efficiency. However, the development of open-shell organic radical materials with stability and high photothermal properties remains a challenge. Among these radicals, the stable and commercialized 4-OH-TEMPO radical molecule has garnered considerable attention in various organic synthesis reactions owing to its unique redox advantages, but it shows less application comparing with the other open-shell organic radicals in photo-thermal conversion. In this study, 4-OH-TEMPO exhibits favorable photothermal properties upon combination with Cu 2 + , thus it is capable of enhancing the reaction rate of HMF oxidation to DFF by a factor of 10 under LED (400 nm). Under illumination of LED, leading to the complete conversion of HMF and the generation of DFF with a yield of 99.7 % within 30 min. Mechanism study shows that the photothermal effect facilitates the kinetic process of the reaction, and accelerated conversion of 4-OH-TEMPO to the oxidatively active species 4-OH-TEMPO + under light-induced action further increased the reaction rate. This research proffers novel insights and references for 4-OH-TEMPO mediated organic synthesis reactions and the design of free-radical photothermal materials.
研究领域:
材料科学
·
有机化学
·
催化
·
光化学
·
热工学
✓ 已验证
产品关联
DOI
高影响因子
CARBOHYDRATE POLYMERS
·
2023
·
IF 11.2
Lu Tang,Bo Wang,Shiru Bai,Bei Fan,Liang Zhang,Fengzhong Wang
Because the traditional preparation methods of cellulose nanocrystals (CNCs) involve chemical pollution issues, in this study, two typical green solvents, alkali/urea solvent (AUS) and deep-eutectic solvent (DES), were used to dissolve insoluble soybean fibers (ISF) extracted from okara and prepare regenerated CNCs (AUS/CNC and DES/CNC), which were further modified by TEMPO oxidation (AUS/T-CNC and DES/T-CNC). The recoveries of AUS and DES were 82.58 % and 84.00 %, respectively. Chemical composition analysis showed high cellulose purity (>95 %) of the regenerated CNCs. FTIR, XRD and 13 C NMR analysis indicated the cellulose structure and polymorph of CNCs. Thermal analysis revealed that the maximum degradation peak of regenerated CNC shifted to a lower temperature. AFM revealed that CNCs exhibited rod-like fiber structures, while AUS-pretreated CNCs exhibited some special spherical fibers. TEMPO oxidation showed an enhancement effect on the characteristics of AUS/T-CNC and DES/T-CNC; DES/T-CNC exhibited higher stability and apparent viscosity than AUS/T-CNC. The DES/T-CNC-based cryogel displayed a higher adsorption capacity for anthocyanin (0.40 g/g) and curcumin (1.09 g/g) with good controlled release capacity. These results indicated that green solvent pretreatment-assisted TEMPO oxidation is a new environmentally friendly and low-cost method for the preparation of CNCs and shows excellent potential in the field of drug loading and controlled release.
研究领域:
材料科学
·
纳米技术
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Pan Pan,Mingming Li,Yuxin Liu,Yisi Feng,Xinglong Li
2,5-diformylfuran (DFF) is a multifunctional intermediate, which can be used in drugs, functional polymers, fluorescent materials and surfactants. In this paper, a TEMPO-assisted magnetic Fe 3 O 4 @SiO 2 @mSiO 2 -NH 2 -Cu(II) catalytic system was developed for the selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran. The structure of Fe 3 O 4 @SiO 2 @mSiO 2 -NH 2 -Cu(II) was double-layer shell-core spherical structure with uniform ordered mesoporous on the surface, amino groups and Cu were evenly distributed in the outer mesoporous. The catalyst was characterized by FT-IR, TEM, EDS, SEM, XRD, BET and VSM. The effects of reaction conditions were investigated in detail. The conversion of HMF was 98.9% and the highest DFF yield was 92.4% under atmospheric oxygen in toluene solvent. The catalytic activity did not decrease significantly after 5 cycles. The catalytic system had good substrate adaptability for benzyl alcohols and aromatic alcohols with satisfactory yield of corresponding aldehydes (91.3–100%). A possible reaction mechanism was also proposed and found that bis(μ-hydroxy) double copper (II) may be the active reactant in oxidation reaction. The system provides a promising industrialized preparation method for DFF.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
CELLULOSE
·
2017
·Vol. 24
·期 11
·5025-5040
·
IF 3.417
Lin Fengcai,You Yuzhe,Yang Xuan,Jiang Xin,Lu Qilin,Wang Ting,Huang Biao,Lu Beili
A facile, green and efficient microwave-assisted method was developed to oxidize cellulose hydrogel beads with neutral 2,2,6,6-tetramethylpiperidinyl-1-oxyl radical (TEMPO)-mediated system. Resulting cellulose beads were investigated by scanning electron microscopy, solid-state 13 C-NMR spectra, and X-ray diffraction. The patterns of 13 C-NMR spectra indicated that the oxidation occurred only at C6 primary hydroxyl carbon, and the carboxyl groups amounted to 1.28 mmol/g in the cellulose beads. The TEMPO-oxidized cellulose beads showed highly porous structures consisting of nano-sized fibrils with retention of original spherical shapes, and the crystallinity index of the cellulose II almost unchanged after oxidation. The maximum adsorption capacity of rhodamine B, auramine O, malachite green and methylene blue on the TEMPO-oxidized cellulose beads was found to be 609, 537, 740 and 873 mg/g, respectively, and the adsorption process was well described by pseudo-second-order kinetics. In addition, desorption tests showed that TEMPO-oxidized cellulose beads could be regenerated by acid treatment and used repeatedly. Thus, TEMPO-oxidized cellulose beads prepared by microwave irradiation can be potentially used for the removal of organic dyes from industrial wastewater.
研究领域:
化学工程
·
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2024
·
IF 5.6
Lin Li,Runkai Wang,Jiangyan Ji,Tong Wu,Dongdong Liu,Xinjian Hu,Fei Chai
This study presents an efficient extraction of nanocellulose crystals (CNCs) and nanofibers (CNFs) through ultrasound-assisted TEMPO oxidation method using deep-processed heavy metal-containing calabash as raw material. The extraction method, integrating TEMPO-mediated oxidation and ultrasound techniques, enhanced the yield of CNCs and CNFs. The results demonstrate that CNCs yielded 63 %, with a carboxyl content of 1.27 mmol/g, while CNFs yielded 31 %, with a carboxyl content of 1.21 mmol/g. CNCs and CNFs exhibited excellent mechanical properties, with CNCs having an average length of 214.4 nm, average diameter of 2.72 nm, and a length-to-diameter ratio of 78.8. CNFs had an average length of 437.8 nm, average diameter of 5.7 nm, and a length-to-diameter ratio of 76.8. X-ray diffraction (XRD) results showed crystallinity of 87.1 % for CNCs and 81.2 % for CNFs. The thermal stability of the fibers was confirmed up to 230℃. The film prepared by combining 10 % PVA with 90 % CNC exhibited a tensile strength of 32.11 MPa, Young's modulus of 2027.1 MPa, and could generate a maximum voltage of 0.83 V. This study provides an effective pathway for the value-added utilization of deep-processed calabash and highlights the broad application prospects of the composite film in the field of flexible sensors.
研究领域:
材料科学
·
环境科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Zuwu Tang,Xinxing Lin,Yalan Chen,Yuwei Pan,Yuqing Yang,Ajoy Kanti Mondal,Meiqiong Yu,Hui Wu
Water pollution is an ongoing trouble that is of significant urgency to resolve worldwide. However, traditional materials used in the process of water purification are costly and energy intensive. The preparation of low-cost, green and sustainable aerogels with low density, high porosity and high specific surface area (SSA) is a great challenge. In this paper, a mussel-inspired, low-cost, polydopamine (PDA)-functionalized TEMPO-oxidized cellulose nanofiber (TOCNF) PDA/TOCNF composite aerogel has been rationally designed and fabricated with low-density, high porosity and high SSA. The PDA/TOCNF composite aerogel shows low density (18.2 mg/cm 3 ), high porosity (98.7 %), and large surface areas (41.3 m 2 /g). The resulting PDA/TOCNF composite aerogel could adsorb a maximum of 314.6 mg/g of methylene blue (MB). The recycle experiment for reusing of adsorbent showed that after five consecutive cycles, the removal ability of MB by the PDA/TOCNF composite aerogel still maintained higher than 90 %. In addition, the PDA/TOCNF composite aerogel also had a high adsorption capacity of heavy metal ions, for example, it adsorbs 446.0 mg/g of Cu 2+ , 222.0 mg/g of Pb 2+ , 267.0 mg/g of Cd 2+ , and 600.0 mg/g of Fe 3+ , respectively. The possible adsorption mechanisms imply that the PDA/TOCNF composite aerogel adsorbs MB due to the synergistic binding interactions, such as electrostatic attraction, π-π stacking interaction, Vander waals force, and hydrogen bonding. Similarly, the PDA/TOCNF composite aerogel adsorbs metal ions due to the electrostatic attraction and chelation of metal ions with the PDA/TOCNF aerogel. Therefore, PDA/TOCNF composite aerogels may have potential applications in wastewater treatment because of their sustainability and low energy consumption.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
·
2018
·
IF 4.667
Mei Cui,Renliang Huang,Wei Qi,Rongxin Su,Zhimin He
2,5-Diformylfuran (2,5-DFF) is an important furan-based chemical with broad application potential. To address the difficulties in isolating/purifying the product and recycling the 2,2,6,6- tetramethylpiperidine-1-oxy (TEMPO)-based catalysts, we employed a solvent with a low boiling point in which TEMPO has a low solubility to investigate the effects of TEMPO and its analogs on catalyzing the oxidation of 5-hydroxymethylfurfural (5-HMF). The results indicated that in ethyl acetate with the substitution of one H of TEMPO at the C4 position with either an acetamido ( NH-Ac), methoxy ( OCH 3 ), hydroxy ( OH) or isothiocyanato ( N C S) group, the resulting compound had a product selectivity similar to that of TEMPO (>86%), except for the 4-isothiocyanato-TEMPO-catalyzed reaction. However, after two Hs were substituted with an oxo group ( O), the catalytic efficiency significantly decreased (product yield 16%, selectivity 52%). Based on both the catalytic efficiency and catalyst solubility, a highly efficient method for preparing 2,5-DFF was established using ethyl acetate as the solvent, 4-acetamido-TEMPO as the catalyst and Fe(NO 3 ) 3 and NaCl as cocatalysts. At 40 °C with a substrate concentration of 0.125 mol/L, 5-HMF was completely converted in 2 h, and the yield of 2,5-DFF was 89%. Moreover, when the substrate concentration increased to 0.25 mol/L, the yield of 2,5-DFF was 87%. When 4-acetamido-TEMPO was recovered by centrifugation, the product yield remained as high as 86% after three cycles, demonstrating good recyclability.
研究领域:
化学工程
·
催化化学
·
绿色化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ORGANIC CHEMISTRY
·
2021
·
IF 4.354
Maolin Wang,Zhenkai Xu,Yi Shi,Fang Cai,Jiaqi Qiu,Guang Yang,Zan Hua,Tao Chen
Polymeric nanoreactors in water fabricated by the self-assembly of amphiphilic copolymers have attracted much attention due to their good catalytic performance without using organic solvents. However, the disassembly and instability of relevant nanostructures often compromise their potential applicability. Herein, the preparation of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-containing nanoreactors by the self-assembly of amphiphilic bottlebrush copolymers has been demonstrated. First, a macromonomer having a norbornenyl polymerizable group was prepared by RAFT polymerization of hydrophobic and hydrophilic monomers. The macromonomer was further subjected to ring-opening metathesis polymerization to produce an amphiphilic bottlebrush copolymer. Further, TEMPO, as a catalyst, was introduced into the hydrophobic block through the activated ester strategy. Finally, TEMPO-functionalized polymeric nanoreactors were successfully obtained by self-assembly in water. The nanoreactors exhibited excellent catalytic activities in selective oxidation of alcohols in water. More importantly, the reaction kinetics showed that the turnover frequency is greatly increased compared to that of the similar nanoreactor prepared from liner copolymers under the same conditions. The outstanding catalytic activities of the nanoreactors from bottlebrush copolymers could be attributed to the more stable micellar structure using the substrate concentration effect. This work presents a new strategy to fabricate stable nanoreactors, paving the way for highly efficient organic reactions in aqueous solutions.
研究领域:
材料科学
·
纳米技术
·
催化
·
聚合物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 45
·期 2
·705-713
·
IF 3.288
Samuthirarajan Senthilkumar,Wei Zhong,Mookan Natarajan,Chunxin Lu,Binyu Xu,Xiaoming Liu
An efficient and green protocol for aerobic oxidation of benzylic alcohols in ethanol using CuI–Y zeolite catalysts assisted by TEMPO (TEMPO = 2,2,6,6-tetramethyl-1-piperidine-N-oxyl) as the radical co-catalyst in the presence of atmospheric air under mild conditions is reported. The CuI–Y zeolite prepared via ion exchange between CuCl and HY zeolite was fully characterized by a variety of spectroscopic techniques including XRD, XPS, SEM, EDX and HRTEM. The incorporation of Cu(I) into the 3D-framework of the zeolite rendered the catalyst with good durability. The results of repetitive runs revealed that in the first three runs, there was hardly a decline in activity and a more substantial decrease in yield was observed afterwards, while the selectivity remained almost unchanged. The loss in activity was attributed to both the formation of CuO and the bleaching of copper into the liquid phase during the catalysis, of which the formation of CuO was believed to be the major contributor since the bleaching loss for each run was negligible (<2%). In this catalytic system, except TEMPO, no other additives were needed, either a base or a ligand, which was essential in some reported catalytic systems for the oxidation of alcohols. The aerobic oxidation proceeded under mild conditions (60 °C, and 18 hours) to quantitatively and selectively convert a wide range of benzylic alcohols to corresponding aldehydes, which shows great potential in developing green and environmentally benign catalysts for aerobic oxidation of alcohols. The system demonstrated excellent tolerance against electron-withdrawing groups on the phenyl ring of the alcohols and showed sensitivity to steric hindrance of the substrates, which is due to the confinement of the pores of the zeolite in which the oxidation occurred. Based on the mechanism reported in the literature for homogenous oxidation, a mechanism was analogously proposed for the aerobic oxidation of benzylic alcohols catalysed by this Cu(I)-containing zeolite catalyst.
研究领域:
化学
·
催化
·
绿色化学
·
材料科学
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2025
·
IF 8.5
Jiahui Lu,Qiu Shi,Yu Rong,Fukun Niu,Chuanxi Xiong,Quanling Yang,Zhuqun Shi
In response to escalating global demands for sustainable technologies, the development of high-performance, safe, and eco-friendly separators of lithium-ion battery have become imperative. Herein, a novel nanocellulose composite aerogel separator (designated TOCN-LiP) was engineered through non-covalent crosslinking between TEMPO-oxidized cellulose nanofibers (TOCN) and a well-designed hyperbranched polymer lithium salt electrolyte (denoted LiP). The TOCN-LiP separator demonstrated enhanced interfacial compatibility with lithium metal anodes and exhibited comprehensive performance improvements compared with original TOCN separators. Notably, the TOCN-LiP-10 architecture displayed a homogeneous three-dimensional porous structure, coupled with exceptional cycling stability and a lithium-ion transference number of up to 0.71, achieving a discharge capacity of 125.1 mA h g −1 after 100 cycles at 0.5C, whereas Celgard2500 achieved only 75.2 mA h g −1 . Furthermore, the TOCN-LiP-10 separator demonstrated excellent thermal stability, maintaining dimensional integrity at 200 °C, along with enhanced safety characteristics absent in commercial separators. By preparing aerogel separators through facile LiP molecular synthesis and its incorporation into TOCN matrix for optimized lithium-ion transport, this work provides an in-depth insight into developing sustainable, safe, and high-performance LIB separators.
研究领域:
材料科学
·
电化学
·
能源存储
·
高分子科学
·
纳米材料
·
可持续技术
·
电池技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2020
·
IF 5.162
Jie Hao,Fangxia Wu,Rong Tang,Yuanyuan Sun,Dehua Liu,Zhenqing Zhang
Oxidized starch (oxStarch) is a major derivative of starch. In present study, 4-acetamide-TEMPO system was firstly applied to prepare specifically oxidized starch, homogeneous 1,4-linked α-D-glucuronan. The impact of oxidant amount, 4-acetamide-TEMPO amount and reaction temperature on the properties of products were investigated. The product structures were characterized with 1 H NMR for degree of oxidation (DO), SEC-MALS for MW, MS for analysis of oxidized oligosaccharides , and in-source fragmented MS for analysis of oxidized polysaccharides . The results showed that the DO of oxStarches increased, but their MWs decreased with the raise of oxidant amount; higher 4-acetamide-TEMPO amount provided higher efficiency of specific oxidation of starch, in which the product has higher DO and MW; no significant difference have been observed between the oxStarches oxidized at 4 and 25 °C, but significant degradation was observed at 50 °C. In each product, having a MW distribution, the portion with smaller size has higher DO. While some unspecific oxidation was still observed observed on the second hydroxyl groups of sugar ring in the following order of priority, position 3 > 2 > 1 > 0.
研究领域:
化学
·
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Marine Life Science & Technology
·
2020
·Vol. 3
·期 1
·85-93
·
IF 0
Chen Rui,Huang Wen-Can,Wang Wei,Mao Xiangzhao
Chitin nanofibers have recently received increased attention and are considered to be a promising material for a wide range of applications because of their excellent characteristics. In this study, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized chitin nanofibers (CNFs) with various oxidation times were prepared and characterized. CNFs with different oxidation times were then utilized for enzyme immobilization, using chymotrypsin as a model enzyme. The effects of oxidation time on enzyme immobilization were explored. Results showed characteristics of chitin nanofibers can be controlled by adjusting oxidation time. CNFs treated with TEMPO for 360 min showed the lowest crystallinity (79.13 ± 1.43%), the shortest length (241.70 ± 74.61 nm), the largest width (12.67 ± 3.43 nm), and the highest transmittance (73.01% at 800 nm). The activity of immobilized enzymes and enzyme loading showed good correlation to the carboxylate content of CNFs. The enzyme efficiency based on CNFs and the content of carboxylate groups peaked at the oxidization time of 60 min. When the additional amount of chymotrypsins (CTs) was 500 or 2000 mg/g carrier, the highest loading amount of CTs was 307.17 ± 4.08 or 726.82 ± 12.05 mg/g carrier, respectively.
研究领域:
材料科学
·
生物技术
·
纳米技术
·
酶工程
✓ 已验证
产品关联
DOI
PubMed
危险品化学品经营许可证（带存储）